Another wiring diagram from a noob....

Midwestdrifter

Engineer In Residence
Outputs near or above the panels rated power are going to be rare, less than 0.1% of the time. It is acceptable to chop off a little bit of performance for this 0.1% in exchange for a saving a fair bit of cash on a new controller.
 

Midwestdrifter

Engineer In Residence
MPPT controllers (the vast majority) cannot be overloaded in this fashion. I am sure there are exceptions. As far as the 0.1%, if you have some data showing total charging hours for the year with output that high, please share.


 
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HarryN

Well-known member
MPPT controllers (the vast majority) cannot be overloaded in this fashion. I am sure there are exceptions. As far as the 0.1%, if you have some data showing total charging hours for the year with output that high, please share.


Thanks for that simulation.

Out of curiosity, does the model show any difference in energy production for San Francisco vs Livermore, CA?

I ask for the obvious reason that they are at nearby, yet have quite different weather.

Note - San Francisco weather is different than San Francisco airport weather. (SFO)
 

OrioN

2008 2500 170" EXT
MPPT controllers (the vast majority) cannot be overloaded in this fashion. I am sure there are exceptions. As far as the 0.1%, if you have some data showing total charging hours for the year with output that high, please share.


How much you want to wager that their controllers are spec'd to at least 1.2kW per, and not 0.7kW?
 

Midwestdrifter

Engineer In Residence
It's not unusual for array to inverter ratios to be between 1.1-1.25. Flat mounted panels or panels without convective cooling along the rear may have ratios as high as 1.4. Most installs are focused on cost/value, not getting as much wattage as possible per roof area. Micro inverters can be more closely matched between panel theoretical and inverter size. A panels "rated" output is just a number used to compare panels. Real world output is almost always lower, except for brief events. Edge of cloud, very cold panels with tracking, etc.

https://news.energysage.com/what-size-solar-inverter-do-i-need/

For the budget concious with flat mounted panels, it can make sense to forgo a more expensive or larger controller, and opt for another panel if roof space allows. There will be some lost harvest at the peaks, but the overall harvest/dollar will increase, especially in hot or cloudy areas.
 
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Midwestdrifter

Engineer In Residence
Thanks for that simulation.

Out of curiosity, does the model show any difference in energy production for San Francisco vs Livermore, CA?

I ask for the obvious reason that they are at nearby, yet have quite different weather.

Note - San Francisco weather is different than San Francisco airport weather. (SFO)
The PVwatts calculator can be decent for small changes in a region. You can enter a specific address, and it will account for temperatures and cloud cover. It won't compensate for hill or local shade effects.
https://pvwatts.nrel.gov/
 

bored

Member
Still Struggling with finding much info for charging the House Battery with the GEN...

Orion 3600 watt 30 amp Generator 120v...

Generator -----> to 12v Convertor.

* Can I just connect this the same way as the shore power to the inverter/convertor

Does amps/watts increase when the power drops to 12v...

Trying to figure out how fast the batteries will charge from the GEN..

I just can't get my head around this portion.
 

HarryN

Well-known member
Still Struggling with finding much info for charging the House Battery with the GEN...

Orion 3600 watt 30 amp Generator 120v...

Generator -----> to 12v Convertor.

* Can I just connect this the same way as the shore power to the inverter/convertor

Does amps/watts increase when the power drops to 12v...

Trying to figure out how fast the batteries will charge from the GEN..

I just can't get my head around this portion.
Connection - yes it is the same concept as plugging into the grid, you just have to be aware of the ground - neutral bonding aspect and transfer switch operation.

Inverter / charger aspect
The inverter / charger specs will tell you how fast that "it" is capable of charging the batteries. I didn't look it up, but IIRC it has ~ 60-70 amp charger built in.

Battery aspect
- Then you look at the battery specs and see what they are capable of absorbing to see if the charge rate is appropriate or needs to be adjusted. For 3 battle born 100s, that is ~ (3 batteries) x (50 amps charge rate) = 150 amps max capability.
- That is the max rate you should design for - from all possible charging sources.

Generator aspect
(60 amps ) x (12 volts) < 1 kW, so the generator should be able to keep up.

Doesn't matter if it is nuclear power plant or a honda 2000, that is how fast it will charge.

Charge time from generator alone
- (3 batteries ) x (100 amp-hrs each) = 300 amp-hrs @ 12 volts

Assume for fun that you are at 30% state of charge and want to go to 90% SOC
- (30%) x (300 amp-hrs) = 100 amp-hrs in the pack
- (90%) x (300 amp-hrs) = 270 amp-hrs goal

(270) - (100) = 170 amp-hrs that you want to put into the pack.

(170 amps) / (60 amps) = ~ 3 hrs.

It is just an example - you have to use the actual numbers from your inverter / charger.
 
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bored

Member
This helps a lot with filling in the pieces. Thank you!


Connection - yes it is the same concept as plugging into the grid, you just have to be aware of the ground - neutral bonding aspect and transfer switch operation.

Inverter / charger aspect
The inverter / charger specs will tell you how fast that "it" is capable of charging the batteries. I didn't look it up, but IIRC it has ~ 60-70 amp charger built in.

Battery aspect
- Then you look at the battery specs and see what they are capable of absorbing to see if the charge rate is appropriate or needs to be adjusted. For 3 battle born 100s, that is ~ (3 batteries) x (50 amps charge rate) = 150 amps max capability.
- That is the max rate you should design for - from all possible charging sources.

Generator aspect
(60 amps ) x (12 volts) < 1 kW, so the generator should be able to keep up.

Doesn't matter if it is nuclear power plant or a honda 2000, that is how fast it will charge.

Charge time from generator alone
- (3 batteries ) x (100 amp-hrs each) = 300 amp-hrs @ 12 volts

Assume for fun that you are at 30% state of charge and want to go to 90% SOC
- (30%) x (300 amp-hrs) = 100 amp-hrs in the pack
- (90%) x (300 amp-hrs) = 270 amp-hrs goal

(270) - (100) = 170 amp-hrs that you want to put into the pack.

(170 amps) / (60 amps) = ~ 3 hrs.

It is just an example - you have to use the actual numbers from your inverter / charger.
 

HarryN

Well-known member
I hope you don't take this as a criticism - because that is not how it is meant - just wanting to add something for completeness.

Xantrex makes the Freedom type inverters in both 12 volt and 24 volt versions, with identical charging "amps" capability.

Using the version designed for 50 amps output, if a system is built using a 24 volt battery bank instead of 12 volts, then the charge rate (in watts) doubles. So using exactly the same components, wiring, bus bars, etc, the system could charge at ~ 2 kW instead of ~ 1 kW. Charge time would drop from ~ 3 hrs to 1.5 hrs.

You know how it is - I can't write a post without trying to get people to use 24 volt systems. :hmmm:

Sort of like Graphite Dave and his inverter - charger concept.

Harry
 

bored

Member
@harry

I can answer that. I wanted to do a 24v system. Makes the most sense. I also wanted to do a Tesla system or build my own Battery Pack.

Sometimes it makes sense to take the past of least resistance.

You have giving some compelling information on the benefits of a 24v system. While these systems are out of my wheelhouse so was a lot of hot rodding I have done on other builds.

Came down to this.
-----This is a one off build for me. It doubtful I will ever build another van again.
-----Everywhere I read it simply said 12v systems are easier. 24v systems cheaper to build
-----Most box-stores sell parts for 12v systems if you are ever in a pinch and need a part
-----If I am in a remote area because of my limited experience I felt a 12v system would be easier to troubleshoot.

That is why I choose a 12v system





I hope you don't take this as a criticism - because that is not how it is meant - just wanting to add something for completeness.

Xantrex makes the Freedom type inverters in both 12 volt and 24 volt versions, with identical charging "amps" capability.

Using the version designed for 50 amps output, if a system is built using a 24 volt battery bank instead of 12 volts, then the charge rate (in watts) doubles. So using exactly the same components, wiring, bus bars, etc, the system could charge at ~ 2 kW instead of ~ 1 kW. Charge time would drop from ~ 3 hrs to 1.5 hrs.

You know how it is - I can't write a post without trying to get people to use 24 volt systems. :hmmm:

Sort of like Graphite Dave and his inverter - charger concept.

Harry
 

autostaretx

Erratic Member
-----Most box-stores sell parts for 12v systems if you are ever in a pinch and need a part
-----If I am in a remote area because of my limited experience I felt a 12v system would be easier to troubleshoot.
I *think* many Big Rigs (i.e. semi-trailer trucks) use 24v for their "driver comfort" accessories.
So 24v parts may be more available than you think. Just drop in at the Peterbuilt and Freightliner service depots (or truck stops).

--dick (has 12v system, so above is hearsay coupled to flaky memory)
 

HarryN

Well-known member
@harry

I can answer that. I wanted to do a 24v system. Makes the most sense. I also wanted to do a Tesla system or build my own Battery Pack.

Sometimes it makes sense to take the past of least resistance.

You have giving some compelling information on the benefits of a 24v system. While these systems are out of my wheelhouse so was a lot of hot rodding I have done on other builds.

Came down to this.
-----This is a one off build for me. It doubtful I will ever build another van again.
-----Everywhere I read it simply said 12v systems are easier. 24v systems cheaper to build
-----Most box-stores sell parts for 12v systems if you are ever in a pinch and need a part
-----If I am in a remote area because of my limited experience I felt a 12v system would be easier to troubleshoot.

That is why I choose a 12v system
Hi, makes perfect sense.

Just for clarity, the house battery pack voltage has really nothing at all to do with the appliance voltage requirements in the van. The battery pack is only there to reasonably efficiently "store power".

- Inverters output 120 vac (or whatever the regional typical is)
- USB is ~ 5 volts
- 12 volt appliances really want 13 volts at the 12 volt plug.

The "internal" DC voltage in my van's house battery is 48 volts, but that is only used by the inverter. Everything else is "regulated 12 volt" or "USB".

I don't own any 48 volt appliances at all.

Sometimes it is convenient to have a power distribution location on both sides of a van. (saves wiring long distances to the battery).

In that case I just run a 24 (or 48 volt) line over to a local DC - DC converter and power a local location, example a normal blue sea fuse block to distribute 12 volts.

I am not sure if it is cheaper or not. I am lazy so I don't like running so many wires around the van.

Some customers are buying 120 vac outlets with a USB port built in. At that point, we aren't far from skipping the need for 12 volt distribution completely.
 

bored

Member
updated....Re: Another wiring diagram from a noob....

Here is the new wire diagram. I was able to take advantage of some Cyber Monday sales and have updated the components.

Anything with an image is already purchased. I will update the wire size and lengths as soon as things start getting mounted. Any help is always appreciated.
 

Attachments

OrioN

2008 2500 170" EXT
The only item that can be attached to the battery negative terminal is the shunt. All other negative cables must be attached to the load side of the shunt, or the meter will not read properly.
Add to that... the 3 batteries need to be wired in parallel & not series.
 

Zundfolge

1-2-4-5-3
Following what MWD said, my preference is to utilize positive and negative busbars. Something like this:

https://www.amazon.com/Blue-Sea-Systems-BusBars-100A-250A/dp/B006VELFDK?th=1

Neg batt terminal > shunt > busbar > all negative connections
Pos batt terminal > fuse > busbar > all positive connections

Fit more than a couple of big lugs on a battery and you're out of space. The busbars allow for a much cleaner install, and if you ever need to disconnect something you don't have to unstack the batt. terminal...
 

bored

Member
Thank you. That will give me a very clean look which is what I am hoping for also.

Following what MWD said, my preference is to utilize positive and negative busbars. Something like this:

https://www.amazon.com/Blue-Sea-Systems-BusBars-100A-250A/dp/B006VELFDK?th=1

Neg batt terminal > shunt > busbar > all negative connections
Pos batt terminal > fuse > busbar > all positive connections

Fit more than a couple of big lugs on a battery and you're out of space. The busbars allow for a much cleaner install, and if you ever need to disconnect something you don't have to unstack the batt. terminal...
 

bored

Member
Thanks. For some reason I mixed up my notes. Solar in Series. Batteries in Parallel..

Thanks for catching that.

Add to that... the 3 batteries need to be wired in parallel & not series.
 

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